How to Find Comps for Property Tax Appeal: A Step-by-Step Guide

Why Comps Matter (More Than You Think)

Your property tax assessment is based on your home's market value.

The assessor estimates that value using mass appraisal techniques. They look at recent sales of similar properties in your area. Those sales are called comparable sales, or "comps."

If your comps show your home is worth less than your assessed value, you have a strong case for a reduction.

But here's what most homeowners get wrong: Not all sales are good comps. A sale from 3 years ago? Not useful. A sale of a house twice the size of yours? Not comparable. A foreclosure sale? Usually excluded.

The right comps can save you 10-15% on your property tax bill.

The wrong comps—or no comps at all—mean you're stuck paying the full assessed amount.

What Makes a Good Comp?

Before you start searching, know what you're looking for.

A good comparable sale has these characteristics:

1. Recent Sale Date

The sale should be within the last 12 months.

Ideally, within 6 months. The closer to your assessment date, the better. Real estate markets change. A sale from 2 years ago might not reflect current market conditions.

Exception: In slow markets or rural areas, you might need to go back 18-24 months. But prioritize the most recent sales first.

2. Similar Location

The comp should be in the same neighborhood or a very similar area.

Same school district. Same general location (within 0.5-1 mile for urban areas, 2-3 miles for suburban/rural). Similar access to amenities, schools, and transportation.

What to avoid: Comps from completely different neighborhoods, even if they're nearby. A house in a gated community isn't comparable to one in a regular subdivision, even if they're on the same street.

3. Similar Property Type

The comp should be the same type of property.

Single-family home vs. single-family home. Condo vs. condo. Townhouse vs. townhouse. Don't mix property types.

Exception: In some areas, townhouses and condos might be comparable if they're similar in size and features. But this is rare. Stick to the same property type.

4. Similar Size

Square footage should be within 10-15% of your home.

If your home is 2,000 square feet, look for comps between 1,700-2,300 square feet. The closer, the better.

Also consider:

5. Similar Condition and Features

The comp should be in similar condition to your home.

Move-in ready vs. move-in ready. Needs updates vs. needs updates. You can't compare a fully renovated home to one that needs $50,000 in repairs.

Key features to match:

6. Arm's Length Transaction

The sale should be a normal, arm's length transaction.

This means:

What to exclude:

Where to Find Comparable Sales

You have several options. Some are free. Some cost money. All have trade-offs.

Option 1: County Assessor/Appraisal District Websites (Free)

Most counties publish recent sales data on their websites.

For Texas homeowners:

For California homeowners:

Pros: Free, official data, includes sale prices and dates

Cons: Limited search filters, may not include all property details, can be hard to navigate

Option 2: Real Estate Websites (Free)

Zillow, Redfin, and Realtor.com show recent sales.

How to use them:

Pros: Easy to use, visual map interface, includes photos and details

Cons: May not include all sales, data can be delayed, some sales might be missing details

Option 3: Public Records (Free, but Time-Consuming)

County recorder's offices keep records of all property transfers.

How to access:

Pros: Most complete data, official records

Cons: Time-consuming, requires manual research, may need to visit in person

Option 4: Real Estate Agents (Free, but Requires Relationship)

Agents have access to MLS (Multiple Listing Service) data.

How to get comps from an agent:

Pros: Professional analysis, access to detailed MLS data, may include insights

Cons: Requires relationship with agent, may try to get your business, data quality varies

Option 5: Paid Services (Costs Money)

Services like ATTOM Data, CoreLogic, or specialized property tax services provide comp reports.

Pros: Comprehensive data, professional analysis, saves time

Cons: Costs money ($50-$500+ depending on service), may not be worth it for a single appeal

When to use: If you're appealing multiple properties, or if you need very detailed analysis

Step-by-Step: How to Find Your Comps

Follow this process to find the best comparable sales for your appeal.

Step 1: Gather Your Property Information

Before you search, know your property details:

Where to find this: Your Assessment Notice (California) or Notice of Appraised Value (Texas), plus your own knowledge of the property.

Step 2: Set Your Search Criteria

Define what you're looking for:

Write these down. You'll use them to filter results.

Step 3: Search Multiple Sources

Don't rely on just one source. Check at least 2-3.

Recommended approach:

Why multiple sources? Different sources may have different sales. Some sales might be missing from one source but present in another.

Step 4: Collect Potential Comps

Gather 8-12 potential comps initially.

For each potential comp, record:

Use a spreadsheet. Make columns for each data point. This makes it easy to compare and filter.

Step 5: Evaluate and Filter

Not all potential comps are good comps. Filter them down.

Eliminate comps that:

Keep the best 3-5 comps.

These should be:

Step 6: Calculate Adjusted Values

Your comps won't be identical to your property. Adjust for differences.

Common adjustments:

How to calculate adjustments:

Example:

Step 7: Determine Your Property's Market Value

Use your adjusted comps to estimate your property's value.

Methods:

Most assessors use the median or a weighted average.

Your estimated market value should be lower than your assessed value. If it's not, you might not have a strong case, or you need better comps.

Common Mistakes to Avoid

Most homeowners make these mistakes when finding comps. Don't be one of them.

Mistake #1: Using Comps That Are Too Old

The problem: Using sales from 2-3 years ago when recent sales are available.

The solution: Prioritize sales within the last 6-12 months. Only use older sales if recent ones aren't available.

Mistake #2: Ignoring Location Differences

The problem: Using comps from different neighborhoods because they're "close by."

The solution: Stick to the same neighborhood or very similar areas. A 5-minute drive can mean a completely different market.

Mistake #3: Not Adjusting for Differences

The problem: Comparing your 1,500 sq ft home to a 2,000 sq ft comp without adjusting.

The solution: Always adjust for size, condition, and feature differences. Show your math.

Mistake #4: Including Non-Arm's Length Sales

The problem: Including foreclosure sales or family transfers as comps.

The solution: Only use normal, arm's length transactions. Exclude foreclosures, short sales, and family transfers.

Mistake #5: Not Having Enough Comps

The problem: Using only 1-2 comps, or comps that aren't very similar.

The solution: Aim for 3-5 strong comps. More is better, but quality matters more than quantity.

Mistake #6: Cherry-Picking the Lowest Sales

The problem: Only using the lowest-priced sales, ignoring higher sales.

The solution: Use all recent, comparable sales. If most sales are higher than your assessment, you might not have a case. Be honest about the market.

How to Present Your Comps in Your Appeal

Finding good comps is only half the battle. You need to present them effectively.

Create a Comp Report

Include:

Format Your Report Clearly

Make it easy for the assessor to understand:

Submit With Your Appeal

Include your comp report with your appeal filing.

For Texas: Submit with your protest to your Appraisal District

For California: Submit with your appeal to your county's Assessment Appeals Board

Deadline reminder: File your appeal before the deadline. Check your deadline here.

When to Get Professional Help

Finding comps can be time-consuming. Sometimes it's worth getting help.

Consider professional help if:

TaxDrop handles comp research as part of our service. We use AI-powered analysis to find the best comparable sales, adjust for differences, and build a strong appeal case. Get your free assessment review to see if we can help.

The Bottom Line

Finding good comparable sales is essential for a successful property tax appeal.

The right comps can prove your home is overassessed. The wrong comps—or no comps—mean you're stuck paying the full amount.

Follow this process:

Most importantly: If your comps show your assessed value is too high, don't wait. File your appeal before the deadline. Every day you delay is another day you're overpaying. See our primary home tax protests page.